Device for imparting linear and rotational motion

ABSTRACT

A power cylinder which provides linear motion and rotational motion at each end of its stroke. The piston has a sleeve through which the rod projects and which sleeve is held from sliding over the rod by coil springs at either end and which has a cam surface in which rides a pin projecting from the rod so that when the piston has pushed the rod to the end of its travel, the forward spring will compress and allow the sleeve to move with respect to the rod so that the cam surface acts on the pin to rotate the rod.

United States Patent [72] Inventor Little York, NJ. [21] AppLNo. 784,613 [22] Filed Dec. 18,1968 [45] Patented June8,1971 [73] Assignee Affiliated Manufacturers, Inc.

[54] DEVICE FOR IMPARTING LINEAR AND ROTATIONAL MOTION 11 Claims, 10 Drawing Figs.

[52] U.S.Cl 74/57, 92/3l,74/99 [51] Int.Cl F16h 15/08, F16h 21/44 [50] FieldotSeareh 74/99, 101-l09,57;92/3l,33

[56] References Cited UNITED STATES PATENTS 840,867 1/1907 Rice, Jr. 74/57 4 i I I I 5' I Z2 7 Frank SCIIBCICI Primary Examiner-Frederick L. Matteson Assistant Examiner-Wesley S. Ratliff, Jr. Attorneys-John E. Wilson and Kenneth H. Murray ABSTRACT: A power cylinder which provides linear motion and rotational motion at each end of its stroke. The piston has a sleeve through which the rod projects and which sleeve is held from sliding over the rod by coil springs at either end and which has a cam surface in which rides a pin projecting from the rod so that when the piston has pushed the rod to the end of its travel, the forward spring will compress and allow the sleeve to move with respect to the rod so that the cam surface acts on the pin to rotate the rod.

'III[ 111111 1 PATENTFUJUH 8m 3.583.245

sum 2 BF 2 INVENTOR. FRANK SZHAfFfR BACKGROUND OF THE INVENTION There are many uses for an apparatus which provides for both linear and rotational movement. As an example, it is often necessary to withdraw a work tool from the line of travel of workpieces between operations and this is often accomplished by pivoting the tool to take it out of contact with the workpiece while at the same time moving the tool linearly and out of the way of a new workpiece which is approaching the work station. The tool is then moved linearly toward the workpiece and the tool is rotated to bring it into engagement with the workpiece which is newly positioned at the work station.

Such devices have several disadvantages. It is impossible to adjust the linear movement of the tool without affecting its simultaneous pivotal movement. Further, at high-production speeds the pivotal movement speeds up as the frequency of the oscillating tool is increased so that the tool strikes the workpiece with considerable force. This can result in excessive wear or rupture of the tool and/or workpiece.

Another use of devices which impart both linear and rotational motion is to transfer workpieces during manufacturing or inspection processes. The disadvantages found when such a device is used to move a work tool are also found in this environment. The linear movement cannot be adjusted without affecting the rotational movement and the rotational movement cannot be adjusted without affecting the linear movement. In order to realize high-production speeds the device must be run so that the force exerted on the workpieces are high when it is picked up and when passed off the device. This can result in an increase in the number of workpieces which are not picked up or passed off and an increase in the number of workpieces which are damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages in the prior art which are discussed above. A power cylinder has a piston with a sleeve positioned between the two coil springs on the piston rod so that when the piston moves, the sleeve and rod move with it until the rod reaches the end of its travel. The sleeve then moves against the spring at its forward end to allow a pin on the rod to be acted upon by a camming surface on the sleeve to rotate the rod.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view with parts broken away of a vacuum cylinder made in accordance with the present invention;

FIG. 2 is a view partly in section taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is a plan view with parts broken away similar to FIG. 1 but showing the present air cylinder with the piston centrally located;

FIG. 4 is a view showing the piston in the position of FIG. 3 but with the broken away portion of the drawing in vertical section;

FIG. 5 is a plan view with parts broken away of the air cylinder of FIG. I but showing the piston at the other end of its stroke;

FIG. 6 is a view similar to FIG. 5 but the broken away portion shows the piston in side elevation;

FIG. 7 is a view partly in section taken along the line 7-7 of FIG. 1;

FIG. 8 is a view partly in section taken along the line 8-8 of FIG. 3;

FIG. 9 is a view partly in section taken along the line 9-9 of FIG. 5; and

FIG. 10 is a view which illustrates the work and withdrawal broken line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown in FIGS. l 6, a power cylinder 20 which has an outer cylindrical cover 22 having ends 24 and 26 which along with the cover 22 define the cylindrical space in which a piston 28 is positioned. The cylinder shown is a vacuum cylinder, the vacuum being pulled through a vacuum line 30 which is connected to the end 24 or a line 32 which is connected to the end 26. In order for the piston 28 to reciprocate, the lines 30 and 32 alternate as the line through which air is withdrawn from the cylinder 20. As air is drawn through the line 30 air is allowed to enter the cylinder through the line 32. Similarly, when air is withdrawn from the cylinder through the line 32, air is allowed to enter through the line 30.

In order to regulate the speed of the piston 28, adjusting screws 34 and 36 are provided. The adjusting screws 34 and 36 project at their ends into the air channels 38 and 40 which respectively lead through the ends 24 and 26 from the ends of the respective air lines 30 and 32. The degree by which each of the adjusting screws 34 and 36 project into its corresponding channel 38 or 40 determine the speed of the piston 28 over one-half of its complete stroke. If it is desired to reduce the speed by which the piston 28 moves toward its left, as shown in the drawings, the adjusting screw 34 is rotated so that its end projects further into the channel 38 and conversely rotating that adjusting screw to partially or fully withdraw its end from the channel 38 will increase the speed of the piston 28 as the vacuum in the line 30 draws it to the left. Adjustments of the adjusting screw 36 will similarly affect the piston 28 in its movement to the right. It should be noted that the adjusting screw 34 will have some effect of the rightward movement of the piston 28 and the adjusting screw 36 will have some effect on the leftward movement of the piston 28 because the channels 38 and 40 also serve to allow air to enter the cylinder when the piston is being drawn away from their respective ends 24 and 26.

The piston 28 acts on a piston rod 46 a member which has at one end a collar 48 held on the piston rod 46 by a retaining bolt 50. Secured to the collar 48 is an arm 52, the purpose of which is explained below.

The stroke of the rod 46 and thus the arm 52 may be adjusted by means of adjustable stops 54 and 56 which are threaded into their respective end plates 24 and 26 and which are hollow to allow the rod 46 to project through them. Secured to the rod 46 outwardly of the stop 54 is a ring 58 and outwardly of the stop 56 is secured a ring 60. Adjusting the stop 54 so that it moves to the right in FIG. 1 while turning the stop 56 so that it also moves to the right will move the limits of the stroke of the rod 46 and arm 52 to the right. Obviously, rotating the stops 54 and 56 to the left will have the effect of moving the limits of the stroke of the tool holder 52 to the left. It should be evident that each of the stops 54 and 56 can be adjusted to vary the length of the stroke of the rod 46 and arm 52.

It has been pointed out that the present invention provides rotational movement after linear movement has been completed. To this end the piston 28 includes an element 64 in the form of an integral sleeve portion through which the rod 46 extends. The ends of the sleeve portion 64 are engaged by two coil springs 66 and 68. The spring 66 is retained between a ring 70 and a pin 72 projecting outwardly from the rod 46. The spring 68 is retained by a ring 74 and a pin 76 which also projects outwardly from the rod 46. The rings 70 and 74 are secured to the rod 46 so that they will not move relatively to it. As shown in FIG. 3 the sleeve 64 may be positioned so that it engages both of the springs 66 and 68. The sleeve 64 is not isolated from the springs 66 and 68 by the pins 72 and 76 because at its ends it has slots 80 and 82 in which the pins 72 and 76 can fit so that the ends of the sleeve 64 can engage against the springs 66 and 68.

A cam slot 86 is also provided on the sleeve 64 and accommodates a cam follower pin 90 which is secured to the rod 46.

The cum slot 86 has ends 92 and 94 which are angularly displaced from the cam slots central portion 96.

The piston 28 as seen best in FIGS. 7, 8 and 9 has at its periphery a radial groove 96 which as seen in FIGS. I, 3 and engages a key 98 which is secured to the inner surface of the cover 22. The groove 96 and key 98 prevent the piston 28 from rotating while allowing it to slide within the cylinder 20.

When the piston rod 46 has been moved to the right as far as it will go, that is, when the ring 58 engages against the stop 54, the pin 76 moves into the slot 82 so that the spring 68 is compressed as shown in FIGS. 1 and 2. The cam follower pin 90 has moved to the end 92 of the cam slot 86 where that pin is oriented as shown in FIG. 7. At thisjuncture the rod 46 will be oriented so that the arm 52 is in the position shown in FIG. 10 so that a work transfer device or tool 100 at its end is in a lowered position.

Exhausting air from the interior of the power cylinder through the vacuum line while allowing air to enter through the line 32 will cause the piston 28 and its integral sleeve 64 to move to the left until the left end of the sleeve 64 abuts against the spring 66 as shown in FIGS. 3 and 4. As shown in these figures, neither of the pins 72 and 76 are all of the way into their respective slots 80 and 82. When the piston 28 is positioned as shown in FIGS. 3 and 4, the cam follower pin 90 is positioned in the central portion 96 of the cam slot 86 so that the pin 90 and the rod 46 are oriented as shown in FIG. 8. Thus, the piston 28, in moving from the position shown in FIGS. 1 and 2, to the position shown in FIGS. 3 and 4, has rotated the piston rod 46 so that the arm 52 is raised to the dotted line position of F IO. 10.

As the exhaustion of air out of the cylinder 20 through the line 30 is continued, the piston 28, through its sleeve 64, pushes against the coil spring 66 to move the piston rod 46 until the ring 60 engages the stop 56. When this happens the rod 46 can move no further and the end of the sleeve 64 compresses the spring 66 as shown in FIGS. 5 and 6. This has the effect of moving the cam follower pin 90 to the end 94 of the cam slot 86 so that the cam follower pin 90 is oriented as shown in FIG. 9 and the piston rod 46 has turned to rotate the arm 52 to bring the tool or transfer device 100 down to a posi tion which as viewed in FIG. 10 would correspond to a working or withdrawal position.

After the tool has completed its operation, air is exhausted out of the cylinder 20 through the line 32. Air is allowed to enter the cylinder 20 through the line 30 so that the piston 58 moves to the right to allow the spring 66 to elongate and the cam follower pin 90 to assume its position in the central portion 96 of the cam slot 86 as shown in FIG. 3. This has the effect of rotating the piston rod 46 so that the arm 52 will assume an angularity suitable for a position as shown in dotted line in FIG. 10.

The air isexhausted out of the line 32 until the ring 58 abuts against the stop 54. When this happens the sleeve 64 continues to slide to the right to cause the cam follower pin 90 to slide to the end 92 of the cam slot 86. This rotates the rod 46 until the arm 52 is lowered to the solid-line position of FIG. 70.

It is possible that the working position of the tool should be at a different height than the withdrawn position. This would be accomplished by making an appropriate change in the profile of the cam slot 86.

It should be understood that the foregoing is only a preferred embodiment of the present invention and that other embodiments can be made which will not depart from the scope thereof.

Iclaim:

1. Apparatus for imparting linear and subsequent rotational movement to a member comprising a movable element; means to bias said member against movement relatively to said element; a stop to limit the displacement of said member; means to move said element in one direction so that said member moves linearly until it engages said stop and said element moves against saidjbias and relatively to said member, and in the opposite direction so that said member moves in the direction of said bias, a cam connected with one of said member and said element and a follower connected with the other said member and said element, said cam and said follower being adapted to rotate said member in one direction of rotation when said element moves relatively to said member against said bias and in the opposite direction of rotation when said element moves in the direction of said bias and relatively to said member.

2. The apparatus defined in claim 1 wherein said member is biased against movement relatively to said element by a spring connected with said member and said element.

3. The apparatus defined in claim 2 wherein said member is a rod and said element is a sleeve slidably mounted on said rod.

4. The apparatus defined in claim 2 further comprising a second spring, said second spring being connected between said member and said element on the side of said element opposite to that of said first defined spring, a second stop positioned so that when said element is moved in said opposite direction said member will move until it is limited in movement by said second stop and said element will move against the bias of said second spring with said cam and said follower operating to rotate said member in a first direction of rotation as said element moves relatively to said member and in a second direction of rotation when said element subsequently moves in the direction of the bias of said second spring and relatively to said member.

5. The apparatus defined in claim 2 wherein said member is a rod and said element is a sleeve slidably mounted on said rod.

6. The apparatus defined in claim 5 wherein said sleeve is mounted so as to be restrained from movement in any direction other than a direction parallel to the longitudinal axis of said rod.

7. The apparatus defined in claim 5 wherein said follower is connected to said rod and said cam is formed in said sleeve.

8. The apparatus defined in claim 5 wherein said sleeve is connected to a piston and said piston is slidably mounted in a power cylinder.

9. A double-acting vacuum cylinder for imparting linear and subsequent rotational movement to a rod, comprising, a piston slidably mounted in said cylinder but secured against rotational movement, two channels on either side of said piston for drawing vacuum alternately to provide a reciprocating motion to said piston, said piston having an integral sleeve slidably mounted on said rod, two springs, one on each side of said sleeve and each being connnected with said rod, a stop for limiting the movement of said rod in one direction, a second stop for limiting the displacement of said rod in the opposite direction, a cam on one of said sleeve and said rod, a follower on the other of said sleeve and said rod, whereby when said piston moves said sleeve in said one direction, said sleeve moves one of said springs which in turn moves said rod until said rod is prevented from moving by said stop and then said piston moves said sleeve relatively to said rod against the bias of said one spring so that said cam and said follower operate to rotate said rod in a first direction of rotation and whereby when said sleeve is moved in the opposite direction until said rod is prevented from further movement by said second stop, further movement of said sleeve against the bias of said second spring will cause said rod to rotate in a second direction of rotation.

10. The cylinder defined in claim 9 wherein each of said channels has an adjusting screw projecting into it for adjusting the flow of air into and out of said cylinder and thus the speed of said reciprocating piston.

11. The apparatus defined in claim 12, further comprising two slots, one at each end of said sleeve, and two pins fixed to and projecting outwardly from such rod, and wherein said sleeve is positioned between said pins and said springs are coil springs encircling said rod and positioned so that each of said pins is between said sleeve and one of said springs to prevent of one of said springs with one of said pins passing within said slot. 

1. Apparatus for imparting linear and subsequent rotational movement to a member comprising a movable element; means to bias said member against movement relatively to said element; a stop to limit the displacement of said member; means to move said element in one direction so that said member moves linearly until it engages said stop and said element moves against said bias and relatively to said member, and in the opposite direction so that said member moves in the direction of said bias, a cam connected with one of said member and said element and a follower connected with the other said member and said element, said cam and said follower being adapted to rotate said member in one direction of rotation when said element moves relatively to said member against said bias and in the opposite direction of rotation when said element moves in the direction of said bias and relatively to said member.
 2. The apparatus defined in claim 1 wherein said member is biased against movement relatively to said element by a spring connected with said member and said element.
 3. The apparatus defined in claim 2 wherein said member is a rod and said element is a sleeve slidably mounted on said rod.
 4. The apparatus defined in claim 2 further comprising a second spring, said second spring being connected between said member and said element on the side of said element opposite to that of said first defined spring, a second stop positioned so that when said element is moved in said opposite direction said member will move until it is limited in movement by said second stop and said element will move against the bias of said second spring with said cam and said follower operating to rotate said member in a first direction of rotation as said element moves relatively to said member and in a second direction of rotation when said element subsequently moves in the direction of the bias of said second spring and relatively to said member.
 5. The apparatus defined in claim 2 wherein said member is a rod and said element is a sleeve slidably mounted on said rod.
 6. The apparatus defined in claim 5 wherein said sleeve is mounted so as to be restrained from movement in any direction other than a direction parallel to the longitudinal axis of said rod.
 7. The apparatus defined in claim 5 wherein said follower is connected to said rod and said cam is formed in said sleeve.
 8. The apparatus defined in claim 5 wherein said sleeve is connected to a piston and said piston is slidably mounted in a power cylinder.
 9. A double-acting vacuum cylinder for imparting linear and subsequent rotational movement to a rod, comprising, a piston slidably mounted in said cylinder but secured against rotational movement, two channels on either side of said piston for drawing vacuum alternately to provide a reciprocating motion to said piston, said piston having an integral sleeve slidably mounted on said rod, two springs, one on each side of said sleeve and each being connnected with said rod, a stop for limiting the movement of said rod in one direction, a second stop for limiting the displacement of said rod in the opposite direction, a cam on one of said sleeve and said rod, a follower on the other of said sleeve and said rod, whereby when said piston moves said sleeve in said one direction, said sleeve moves one of said springs which in turn moves said rod until said rod is prevented from moving by said stop and then said piston moves said sleeve relatively to said rod against the bias of said one spring so that said cam and said follower operate to rotate said rod in a first direction of rotation and whereby when said sleeve is moved in the opposite direction until said rod is prevented from further movement by said second stop, further movement of said sleeve against the bias of said second spring will cause said rod to rotate in a second direction of rotation.
 10. The cylinder defined in claim 9 wherein each of said channels has an adjusting screw projecting into it for adjusting the flow of air into and out of said cylinder and thus the speed of said reciprocating piston.
 11. The apparatus defined in claim 12, further comprising two slots, one at each end of said sleeve, and two pins fixed to and projecting outwardly from such rod, and wherein said sleeve is positioned between said pins and said springs are coil springs encircling said rod and positioned so that each of said pins is between said sleeve and one of said springs to prevent said springs from working against each other, whereby, when said sleeve moves in either of said directions until said rod engages one of said stops, said sleeve will move against the bias of one of said springs with one of said pins passing within said slot. 